The present invention pertains generally to industrial curtains used as environmental closures for openings through which traffic can still pass. The curtains generally comprise a plurality of usually transparent strips that are suspended contiguously to each other from a hanger or support generally fixed adjacent to a top margin of the opening. Each of the strips usually consists of a length of flexible, generally transparent, material terminating adjacent to a lower margin of the opening. The present invention relates particularly to an improved support from which the industrial strip curtain can be suspended.
Industrial curtains are conventionally employed to provide closures between, for example, separate manufacturing areas within large buildings, warehouses and the like. Goods are often required to be transported from one area of a manufacturing or storage facility to another where one or the other of the areas is heated, air-conditioned or even refrigerated. Sometime other environmental concerns need to be addressed such as dust, fumes, smoke, dirt, or even noise. Where the traffic is only occasional, conventional doors can be employed to close any doorway between the two areas. Where the traffic is considerable, the use of conventional doors gives way to suspended flexible screens or curtains, which inhibit the wholesale transfer of air from one area to the other yet still permit goods-transporting vehicles to pass through with little effort.
These curtains are generally made up of side-by-side elongated plastic strips that hang from a support system mounted to extend across the top of the opening. For safety reasons, it is desirable that the curtain be sufficiently transparent that one operating a transporting vehicle be able to see any hazard or obstruction that might exist on an opposite side of a curtain before proceeding through. Persons on the opposite side of a curtain also desire to be able to see oncoming transport vehicles so appropriate evasive action can be taken. Thus, plastic materials, which were more or less transparent, such as polyvinyl chloride and polyethylene, were adopted as the preferred materials for forming such screens as shown, for example, in U.S. Pat. Nos. 4,095,642, 4,165,778, 4,232,725, and 4,607,678.
Many different support systems have been developed for these strip curtains. One type of support system involves each strip forming the curtain having a loop for receiving a horizontal rod that is mounted adjacent to the top of the opening covered by the curtain by two or more brackets. Examples of this type of support system are disclosed in U.S. Pat. Nos. 4,095,642; 4,384,606; 4,515,202; and 6,213,437. A related type of support system is disclosed in U.S. Pat. Nos. 4,257,471 and 4,776,382 wherein the loops at the top of each strip are formed by separate structural hangers that loop over the horizontal rod and are coupled to each strip forming the curtain. A common disadvantage of such support systems is the tendency for the horizontal rod to sag between supports, which can cause an uneven hang to the strips forming the curtain.
To avoid this disadvantage, some much more complicated hanger schemes have been devised as shown in U.S. Pat. Nos. 4,312,396; 4,335,777; 4,340,106; 4,388,961; 5,146,971; 5,520,237; and 6,050,322 that commonly use extruded profiles or similar structures that are secured adjacent to the top of the opening to be covered by the curtain. The extruded profiles are design to mate with other formed hanger members coupled to the strips forming the curtain. None of these systems have gained wide acceptance, perhaps due to the time involved in assembly of the curtain strips to the hangers and the occasionally awkward engagement between the hangers and the supporting profiles or equivalent structures. Much more simple structures are to be found in U.S. Pat. Nos. 4,165,778; 4,232,725, 4,289,190; and 4,607,678 that disclose a series of threaded fasteners such as a bolts or the like penetrating a series of holes located in the upper ends of each strip. Mating fasteners are engaged on the bolts over the strips to hold the strips in place. The assembly of such structures has been found to be a very time-consuming, repetitive activity, which is often not completed in an entirely satisfactory way, thus leading to later disengagement by the mating fasteners causing the strips to fall away from the support system.
A strip curtain support system that permits fast and easy assembly is disclosed in U.S. Pat. No. 5,127,460. The support comprises a bar having a series of pegs spaced equidistance from each other along the length of the bar. Each peg includes a leg extending substantially perpendicularly outward from the bar. A foot is fixed to each leg so that each foot extends downwardly perpendicular to the stalk and is spaced from the bar. The strips forming the curtain have multiple holes near the top of each strip, which are spaced the same distance from each other as the distance between the pegs. The strips can be suspended from a plurality of the pegs by manipulating the multiple holes upward over the feet and onto the leg portion of each peg. Unfortunately, the downwardly projecting portion of each foot acts, over time, as a lever pressed by the moving curtain that flexes the base of each leg adjacent to the strip upward and downward to such an extent that the support fails by the leg breaking away from the supporting bar.
Accordingly, what is needed is a strong strip curtain support system that allows for fast and easy assembly, yet is sufficiently strong that product failure due to flexing or any other action is unlikely to occur. What is further needed is such a strip curtain support system that permits the curtain strips to be easily changed when the strips become worn or abraded, or for other reasons need moved.